Working with CloudKit

import CloudKit

let container = CKContainer(identifier: "com.myapp.container")
let publicDatabase = container.publicCloudDatabase

let record = CKRecord(recordType: "User")
record["name"] = "John Doe"
record["email"] = "john@example.com"

let publicDatabase = CKContainer.default().publicCloudDatabase
publicDatabase.save(record) { (savedRecord, error) in
    if let error = error {
        print("Error saving record: " + error.localizedDescription)
    } else {
        print("Record saved successfully")
    }
}

let privateDatabase = CKContainer.default().privateCloudDatabase
let query = CKQuery(recordType: "User", predicate: NSPredicate(value: true))

privateDatabase.perform(query, inZoneWith: nil) { (records, error) in
    if let error = error {
        print("Error fetching records: " + error.localizedDescription)
    } else if let records = records {
        print("Fetched " + String(records.count) + " records")
    }
}

import CloudKit

let record = CKRecord(recordType: "User")
record["name"] = "John Doe"
record["email"] = "john@example.com"
record["age"] = 30

let record = CKRecord(recordType: "Task")
record["title"] = "Buy groceries"
record["completed"] = false

let database = CKContainer.default().publicCloudDatabase
database.save(record) { record, error in
    if let error = error {
        print("Save error: \(error)")
    } else {
        print("Record saved successfully")
    }
}

import CloudKit

let container = CKContainer.default()
let database = container.publicCloudDatabase

let query = CKQuery(recordType: "Photo", predicate: NSPredicate(value: true))

database.perform(query, inZoneWith: nil) { (records, error) in
    if let error = error {
        print("Error fetching records: \(error)")
        return
    }

    guard let records = records else { return }
    for record in records {
        print("Fetched record: \(record.recordID)")
    }
}

let predicate = NSPredicate(format: "name CONTAINS[cd] %@", "John")
let query = CKQuery(recordType: "User", predicate: predicate)

let startDate = Calendar.current.date(byAdding: .day, value: -7, to: Date())!
let endDate = Date()
let predicate = NSPredicate(format: "creationDate >= %@ AND creationDate <= %@", startDate as CVarArg, endDate as CVarArg)
let query = CKQuery(recordType: "Event", predicate: predicate)

let namePredicate = NSPredicate(format: "name CONTAINS[cd] %@", "John")
let statusPredicate = NSPredicate(format: "status == %@", "active")
let compoundPredicate = NSCompoundPredicate(andPredicateWithSubpredicates: [namePredicate, statusPredicate])
let query = CKQuery(recordType: "User", predicate: compoundPredicate)

let database = CKContainer.default().publicCloudDatabase
let record = CKRecord(recordType: "Task")
database.save(record) { (savedRecord, error) in
    if let error = error {
        switch error {
        case CKError.networkFailure:
            print("Network issue, retry later")
        case CKError.notAuthenticated:
            print("User not logged into iCloud")
        default:
            print("CloudKit error: \(error.localizedDescription)")
        }
    } else {
        print("Record saved successfully")
    }
}

import CloudKit

let subscription = CKQuerySubscription(
    recordType: "User",
    predicate: NSPredicate(value: true),
    subscriptionID: "user-changes",
    options: .firesOnRecordCreation
)

let notificationInfo = CKSubscription.NotificationInfo(
    alertBody: "A user record was updated",
    shouldSendPushNotification: true
)

subscription.notificationInfo = notificationInfo

CKContainer.default().publicCloudDatabase.save(
    subscription,
    completionHandler: { (savedSubscription, error) in
        if let error = error {
            print("Error saving subscription: \(error)")
        } else {
            print("Subscription saved successfully")
        }
    }
)

let share = CKShare(record: record, container: container)
share.title = "Shared Record"
share.message = "Check out this shared record!"

let database = CKContainer.default().publicCloudDatabase
database.save(share) { (savedShare, error) in
    if let error = error {
        print("Error saving share: \(error)")
    } else {
        print("Share saved successfully")
    }
}

import CoreData

let persistentContainer = NSPersistentCloudKitContainer(name: "MyAppModel")
persistentContainer.loadPersistentStores { _, error in
    if let error = error {
        print("Core Data error: \(error)")
    }
}

let context = persistentContainer.newBackgroundContext()
let fetchRequest: NSFetchRequest<MyEntity> = MyEntity.fetchRequest()
fetchRequest.predicate = NSPredicate(format: "isSynced == %@", NSNumber(value: true))

do {
    let results = try context.fetch(fetchRequest)
    // Process fetched entities
} catch {
    print("Fetch error: \(error)")
}